1. You can only sign up to the site once from any household as the address and ip address need to be unique. So for example, if you lived with your mum and your dad they couldn't be your referral for you.
2. You can only do each offer once, but don't panic there are plenty to choose from. and they change once in a while, so if you are not interested in the ones offered at that moment, wait a while and something interesting might come up for you.
3. Don't spam your link!!
4. Join eXceem, for more advice, and tips. They'll be glad to help, just don't post your link on there.